Laser imagers are widely used in the medical imaging field to produce visual representations on film of digital medical images. Laser imagers typically include a film supply and transport system, a film exposure system, and a film processing system. The film supply and transport system includes a supply of unexposed film stacked in a cartridge or magazine, a mechanism for removing individual sheets of film and delivering each sheet to a film transport system. The film transport system then transports the film through the film exposure and film processing systems to an output tray for access by a user.
U.S. Pat. No. 6,260,842, issued Jul. 17, 2001, inventors Nelson et al. disclose a film supply system for use with a resealable film cartridge containing a stack of unexposed film. The film supply system includes a mechanism for unsealing the cartridge and a mechanism for separating and delivering individual film sheets to the film transport system. As disclosed, the top film is gripped by a suction cup mechanism, the film is bent and the film is separated from the next adjacent film in the stack and delivered to a feed roller pair. Initially, the film contacts the lower drive roller, the upper idler roller being held out of contact with the lower roller. Then, the rollers are driven closed to secure the film. The rollers are now driven to transport the film away from the film supply system.
Although successful for its intended purposes, the disclosed feed roller mechanism evidenced certain features that needed improvement. These include the following:
1. The idler roller would not clamp evenly across the drive roller.
2. The motor was under load while the idler roller was in the open position, making it susceptible to closing when the motor was not energized.
3. Link mechanisms in the front of the mechanism made it difficult to clear films in the assembly.
4. The stack height of the mechanism was to high for the synergy application.